#include<stdio.h>
int main()
{
    int x,y;
    scanf("%d",&x);
    if(x>3&&x<=9)y=x*(x+2);
    else if(x>-1&&x<=3)y=2*x;
    else if(x<=-1)y=x-1;
    else y=-1;
    printf("%d\n",y);
    return 0;
}